SYSTEM_QUERY_PERFORMANCE_COUNTER_INFORMATION

The SYSTEM_QUERY_PERFORMANCE_COUNTER_INFORMATION
structure provides input to and receives output from the ZwQuerySystemInformation or
NtQuerySystemInformation functions when given the
information class SystemQueryPerformanceCounterInformation
(0x7C).

Documentation Status

The SYSTEM_QUERY_PERFORMANCE_COUNTER_INFORMATION
structure used not to be documented. It still has no C-language definition in any
header, including WINTERNL.H, from any known development kit. It is however documented
with NtQuerySystemInformation as found online today,
28th October 2016. When it was added may be anyone’s guess.

Layout

The SYSTEM_QUERY_PERFORMANCE_COUNTER_INFORMATION
is 0x0C bytes in both 32-bit and 64-bit Windows.

Offset

Definition

Remarks

0x00

ULONG Version;

input, must be 1

0x04

QUERY_PERFORMANCE_COUNTER_FLAGS Flags;

output

0x08

QUERY_PERFORMANCE_COUNTER_FLAGS ValidFlags;

output

The QUERY_PERFORMANCE_COUNTER_FLAGS structure is
just a packaging of ULONG bit fields. While it seems not
to be used elsewhere, it may as well be presented here: